[Coral-List] Michael Risk - C. delitrix as measure of bioerosion

Gregor Hodgson gregorh at reefcheck.org
Mon Oct 16 22:48:02 EDT 2006

Mike has long suggested the use of boring sponges as a useful/simple
technique for estimating one component of reef health. We are always open to
good suggestions and this idea is appealing, however, our initial tests did
not support the theory. To be useful to us, this indicator needs to work at
least regionally if not globally. But we have not given it a rigorous test.

We would be very pleased if Mike (or supporter) would suggest a volunteer
level protocol and then if teams around the world might give it a test to
see if it holds up as an indicator on a wide geographic scale. 


Gregor Hodgson, PhD
Executive Director, Reef Check Foundation
P.O. Box 1057 (mail)
17575 Pacific Coast Highway (Fedex)
Pacific Palisades, CA 90272-1057
Tel: +1-310-230-2371 Fax: +1-310-230-2376
email: gregorh at reefcheck.org
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-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov] On Behalf Of Jon Rohde
Sent: Saturday, October 14, 2006 7:37 PM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Michael Risk - C. delitrix as measure of bioerosion

Michael Risk

I have long wondered about the role of boring sponges which seem, to my
unpracticed eye, to be ever more prevalent on Bahamian reefs - where I spend
half the year.  As you note, there seems to be little attention to them yet
they are relatively easily quantified by amateurs like me.  I have joined
Reef Check and conducted surveys with their few indicator species to
document some Bahamian reefs, but wondered about the rapidly increasing
algae and boring sponges which are neither counted nor mentioned in this
simple methodology, but seem to comprise large portions of our reefs

Could you give me some accessible references to C. delitrix and other boring
sponges?  Do you think that their inclusion in standardized reef surveys
would be a useful tool to document bioerosion?

Thanks for this interesting lead.

Jon Rohde, MD
3 Moray Place
Orangezicht, Cape Town, 8001
tel 27-(0)21-465-0569
Cell 27 (0)83-306-7701

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